title: Conversation effects on neural mechanisms underlying reaction time to visual events while viewing a driving scene: fMRI analysis and asynchrony model.
abstract: This neuroimaging study investigated the neural mechanisms of the effect of conversation on visual event detection during a driving-like scenario. The static load paradigm, established as predictive of visual reaction time in on-road driving, measured reaction times to visual events while subjects watched a real-world driving video. Behavioral testing with twenty-eight healthy volunteers determined the reaction time effects from overt and covert conversation tasks in this paradigm. Overt and covert conversation gave rise to longer visual event reaction times in the surrogate driving paradigm compared to just driving with no conversation, with negligible effect on miss rates. The covert conversation task was then undertaken by ten right-handed healthy adults in a 4-Tesla fMRI magnet. We identified a frontal-parietal network that maintained event detection performance during the conversation task while watching the driving video. Increased brain activations for conversation vs. no conversation during such simulated driving was found not only in language regions (Broca's and Wernicke's areas), but also specific regions in bilateral inferior frontal gyrus, bilateral anterior insula and orbitofrontal cortex, bilateral lateral prefrontal cortex (right middle frontal gyrus and left frontal eye field), supplementary motor cortex, anterior and posterior cingulate gyrus, right superior parietal lobe, right intraparietal sulcus, right precuneus, and right cuneus. We propose an Asynchrony Model in which the frontal regions have a top-down influence on the synchrony of neural processes within the superior parietal lobe and extrastriate visual cortex that in turn modulate the reaction time to visual events during conversation while driving.
authors.affiliation: Department of Communications Sciences and Disorders, Wayne State University, 207 Rackham Hall, 60 Farnsworth St., Detroit, MI 48202, USA. lihsieh@wayne.edu
authors.forename: Li
authors.initials: L
authors.lastname: Hsieh
authors.forename: Richard A
authors.initials: RA
authors.lastname: Young
authors.forename: Susan M
authors.initials: SM
authors.lastname: Bowyer
authors.forename: John E
authors.initials: JE
authors.lastname: Moran
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Genik
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Green
authors.forename: Yow-Ren
authors.initials: YR
authors.lastname: Chiang
authors.forename: Ya-Ju
authors.initials: YJ
authors.lastname: Yu
authors.forename: Chia-Cheng
authors.initials: CC
authors.lastname: Liao
authors.forename: Sean
authors.initials: S
authors.lastname: Seaman
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D001334:Automobile Driving / Q000523:psychology*; D001921:Brain / Q000033:anatomy & histology / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008875:Middle Aged; D008959:Models, Neurological; D009039:Motion Perception / Q000502:physiology*; D009415:Nerve Net / Q000033:anatomy & histology / Q000502:physiology; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology; D013997:Time Factors; D014705:Verbal Behavior / Q000502:physiology*; D055815:Young Adult